a/c zones switching randomly

[ammolance]

Hello, I searched the Shop Talk, and couldn't find an answer so certain y'all can help. Recently, my a/c will randomly switch zones (if I have it on normal or max) when I initially start up (it'll go through the floor, defrost, vents) then about 5-10 mins later "level out" and blow through the vents as it should. Super frustrating. Any advice?

[Gryphonzus]

It is most likely your EATC module. That is the module in the dash that you use to set your air and heat with. There are rubber grommets inside that get old and do not seal so it causes your changes in settings. Search under EATC repair and you will find information about how to repair it. Or you can PM Fastblackmerc and he will fix it for you for a modest fee.

[tbone]

I like your screen name.....

https://www.youtube.com/watch?v=A3LK1CChb08

[fastblackmerc]

Hello, I searched the Shop Talk, and couldn't find an answer so certain y'all can help. Recently, my a/c will randomly switch zones (if I have it on normal or max) when I initially start up (it'll go through the floor, defrost, vents) then about 5-10 mins later "level out" and blow through the vents as it should. Super frustrating. Any advice?

Most likely it's your EATC o-rings. I can repair it for you and upgrade the button & fan wheel lights to LEDs.

[Invective]

Hello, I searched the Shop Talk, and couldn't find an answer so certain y'all can help. Recently, my a/c will randomly switch zones (if I have it on normal or max) when I initially start up (it'll go through the floor, defrost, vents) then about 5-10 mins later "level out" and blow through the vents as it should. Super frustrating. Any advice?

What are the outside temps and what temp is the unit set at when it does this? Is this new behavior? Are you new to the car?

I'm new to the Marauder, having bought mine in late March. I've noticed that if I start my unit when outside temp is in the mid 60s or lower (first thing in the morning) and the unit is set to the mid 70s for higher it will automatically start in the defrost mode. The unit will switch to the dash vents once the outside temp rises and/or I lower the internal setting. If I remember correctly, both my '71 and '79 Cadillacs with the Climate Control did the exact same thing.:coolman:

[ammolance]

Most likely it's your EATC o-rings. I can repair it for you and upgrade the button & fan wheel lights to LEDs.


That'd be awesome, but I'm down in the panhandle of FL now (Panama City).

[ammolance]

What are the outside temps and what temp is the unit set at when it does this? Is this new behavior? Are you new to the car?

I'm new to the Marauder, having bought mine in late March. I've noticed that if I start my unit when outside temp is in the mid 60s or lower (first thing in the morning) and the unit is set to the mid 70s for higher it will automatically start in the defrost mode. The unit will switch to the dash vents once the outside temp rises and/or I lower the internal setting. If I remember correctly, both my '71 and '79 Cadillacs with the Climate Control did the exact same thing.:coolman:


I've had Mickey for a few years now. He just started doing it here recently (past month). It seems like the defrost comes on, then floor, then vents, then somewhere!

[ammolance]

I like your screen name.....

https://www.youtube.com/watch?v=A3LK1CChb08


Thx. What I do in the USAF.

[RubberCtyRauder]

That'd be awesome, but I'm down in the panhandle of FL now (Panama City).

The eatc unit comes out, has to come out to fix anyway, send and get back in a day or two.

[fastblackmerc]

The eatc unit comes out, has to come out to fix anyway, send and get back in a day or two.

That is correct.

[ammolance]

That is correct.


Sir, I truly appreciate the confidence...but in no way (unless its super painless) do I want to try and remove the eatc (probably botched that acronym up), especially in this car. I don't mechanic, electric, plumb, build, etc. I break stuff - plain and simple. I stick to my job, and am good at it. IF it is an easy removal, I may attempt it with some adult (mechanic friend) supervision, and am otherwise open to any suggestions!

[RubberCtyRauder]

There is instructions in the DIY forum and numerous YouTube vids most likely

[Mr. Man]

I thought the EATC defaults to defrost when it craps out. If your system is switching from vent to vent that sounds normal for Automatic mode, in other words the car decides where it needs to send the heated/cooled air most.

[RF Overlord]

If there is a complete loss of vacuum, Mr. Man is correct...the system will switch to defrost and stay there, however if there is a small leak, such as from one or more bad o-rings, the system can operate normally at high-vacuum low-load such as idling or just cruising at 40 on a flat road. When load increases, necessitating a further push on the gas pedal, vacuum drops and the system will go wonky. When you return to a cruise situation, or are decelerating, the system regains vacuum levels and begins to operate normally again. This could account for your seemingly "random" changes in the air outlet position.

[ammolance]

What local auto parts store would sell genuine ford/mercury parts? Need to fix this today. Digging up the wind shield in the morning into the sun = can’t see!

[ammolance]

What local auto parts store would sell genuine ford/mercury parts? Need to fix this today. Digging up the wind shield in the morning into the sun = can’t see!

[RubberCtyRauder]

you need 007 silicone o rings, try NAPA ..not the whole eatc unit


https://www.youtube.com/watch?v=T7dLc8dbTbI

[RF Overlord]

What RCR said ^^^ The o-rings should be silicone or you'll eventually be doing the job twice.

There's a nice write up in the DIY Resource Room.

[ammolance]

That is correct.


PM sent good sir!

[ammolance]

PM sent good sir!

fastblackmerc, sent you a PM the other day, did you receive it? Thanks! -LDA